2007 > 2.7L V6 GASOLINE >
Electronic Control System
DESCRIPTION
The electronic control system used in the new generation auto transaxle is far superior to the previous systems. This
system is able to adopt a variable shift pattern for smooth and problem free shifting.
A solenoid valve is applied to each of the clutches and brakes and is independently controlled. Feedback control and
correction control is performed in all gears as well as utilization of mutual control system to increase shift feeling.
The torque converter damper clutch uses a partial lock up and full lock - up system. An additional control method called
the HIVEC system (neural network) is adopted to increase shift feeling.
Block Diagram (CAN)
ELECTRIC CONTROL LOCATION
The TCM(PCM) is located on the intake manifold in the engine room.
OPERATING COMPONENTS AND FUNCTIONS
SensorFunction
Input shaft speed sensor Detect turbine speed at UD retainer
Output shaft speed sensor Detect T/F drive gear speed at T/F driven gear (4A/T)
Crank angle sensor Detect engine speed
TPS(Gasoline) Throttle opening ratio by potentiometer
Air conditioner switch A/C load by thermister
Inhibitor switch Select lever position by contact switch
Brake switch Brake pedal position
Vehicle speed sensor Detect vehicle speed by speedometer driven gear
Sport mode switch Sport mode On/Off signal
Sport mode up- shift switchSport mode up- shift signal
Sport mode downshift switch Sport mode downshift signal
Request of torque reduction Send the request of torque reduction to ECM
ABS - ECM, Engine ECM In case of CAN communication
Sports Mode
Sports Mode Switch
Sports mode allows the manual up- shift and downshift with the accelerator pedal is depressed. The prompt response
and shift would be obtained due to the continuous shifting without cutting of driving power. The shifting time is also
decreased about 0.1sec during up- shift, 0.2sec during downshift. As the selector lever is pushed upward or downward
one time, the gear is up shifted or downshifted by one gear.
Signals of sports mode switch
Items Mode S/WUP S/WDOWN S/W
D range selection OFFOFFOFF
Sports mode selection ONOFF OFF
Sports mode up- shift selection ONONOFF
Sports mode downshift selection ONOFF ON
Controller Area Network (CAN)
Previously, for different computers in the vehicle to share the same information, each signal required a different pin
and wiring. However, with the introduction of a CAN system, only two lines are required to achieve the same function.
The information is in digital format. This method does not use an integrated ECM.
Input signals to TCM(PCM) through ‘CAN communication’
- Engine rpm, TPS signal
- A/CON signal, Engine coolant temperature
- Quantity of intake airflow, Vehicle speed
- Shift holding signal (FTCS ON)
Output signals from TCM(PCM) through ‘CAN communication’
- Request signal for torque reduction
- ATF temperature, TCM(PCM) type, TCM(PCM) error or not
- Damper clutch ON, OFF / Gear position
TCM PIN DESCRIPITION
PIN
No.Check item
Condition Input/Output value
Measurement
Value Remarks
Type Level
A01 2nd CAN_HI -- - --
A02 2nd CAN_LO -- - --
A03 P Range
Selection P Position
OtherwiseDC
Voltage V_BAT
Max. 1.0V 12.9V
0V
A04 R Range
Selection R Position
Otherwise DC
Voltage V_BAT
Max. 1.0V 12.3V
0V
A05 N Range
Selection N Position
Otherwise DC
Voltage V_BAT
Max. 1.0V 13.2V
0V
A06 D Range
Selection D Position
Otherwise DC
Voltage V_BAT
Max. 1.0V 13.2V
0V
A07 Select Position -DC
Voltage V_BAT
Max. 1.0V 13.2V
0V
A08 Up Position -DC
Voltage V_BAT
Max. 1.0V 13.2V
0V
A09 Down Position -DC
Voltage V_BAT
Max. 1.0V 13.2V
0V
A12 N.A -- - -
A14 N.A -- - -
A19 N.A -- - -
A20 A/T Control Relay Relay On
Relay Off
DC
Voltage V_BAT
Max. 1.0V
Vpeak : Max. 70V
Resistance : 680Ω 13.8V
0V
- 0.7V
Resistance : 680Ω
W/H Open DTC Spec : P0890DTC : P0890
A27 Diagnosis "K" Communicated with
GST Pulse At transmitting
HI : V_BAT* 80%↑
LO : V_BATÎ20%↓ AT receiving
HI : V_BAT* 70%↑
LO : V_BAT*30%↓ 11.3V
0.14/ 0.32V V_BAT :
13.2V
changed by VFS so the control pressure becomes unstable and some hydraulic pressure oscillation occurred. That is
why the reducing pressure has been added in the hydraulic circuit of VFS system for both 4th and 5th speed A/T.
The reducing pressure is about 6.5bar and this value does not be changed regardless of the driving or engine load
condition. Be sure that the conventional line pressure is used for the ‘supply pressure’ of Low&Reverse, Reduction
solenoid because the variable line pressure is not available at reverse range.
HYDRULIC PRESSURE TABLE
Under the constant current amount of VFS (200mA), the line pressure will become as below table. Be sure that the
following data can be achieved by specific special facility or device to check the performance of A/T assembly (not on
the vehicle), however we can refer the maximum pressure value according to each element.Solenoid valve Duty( Ë)
Measured Element Pressure kPa(Psi)
LR 2ND UDODRED*
0 100 0100 0
LR 1030±20(149±3)
60 ↑↑↑↑ 520±40(75±6)
75 ↑↑↑↑ 230±40(33±6)
100 ↑↑↑↑ 0
100 00100 0
2ND 1030±20(149±3)
↑ 60 ↑↑↑ 550±40(80±6)
↑ 75 ↑↑↑ 220±40(32±6)
Low&Reverse brakeLRHold LR annulus gear and OD carrier
Second brake 2NDHold reverse sun gear
One way clutch OWCRestrict the rotating direction of low & reverse annulus gear
Operating elements
UD/COD/CREV/C 2ND/B LR/BOWC
P ●
R ●●
N ●
D1 ● ●○
D2 ● ●
D3 ●●
D4 ●●
1) ○ : OWC is operated when shifts from 1st gear to 2nd gear.
2) L&R brake is released in 1st gear when the vehicle speed is more than 5KPH approximately.
Torque converter and shaft
The torque converter consists of an impeller(pump), turbine and stator assembly in a single unit. The pump is
connected to the engine crankshaft and turns as the engine turns. This drawing force is transmitted to the turbine
through the oil which is recycled by the stator.
The transmission has two parallel shafts ; the input shaft and the output shaft. Both shafts are in line with the engine
crankshaft. The input shaft includes the overdrive clutch, reverse clutch, underdrive clutch, one way clutch, 2ND brake,
low&reverse brake, overdrive planetary carrier, output planetary carrier and transfer drive gear. The output shaft
includes the transfer driven gear.
CLUTCHES
The gear changing mechanism utilizes three multi- disc clutches. The retainers of these clutches are fabricated from
high- precision sheet metal for lightness and ease of production. Also, more responsive gearshifts at high engine
speeds are achieved by a pressure- balanced piston mechanism that cancels out centrifugal hydraulic pressure. This
mechanism replaces the conventional ball check valve.
UNDERDRIVE CLUTCH
The underdrive clutch operates in 1st, 2nd, and 3rd gears and transmits driving force from the input shaft to the
underdrive sun gear(A).
The components comprising the under clutch are as illustrated below.
functioning.c.
Malfunction of the TCM(PCM)
Driving impossible Starting impossible
Starting is not possible when the selector
lever is in P or N range. In such cases, the
cause is probably a defective engine system,
torque converter or oil pump. a.
Malfunction of the engine system
b. Malfunction of the torque converter
c. Malfunction of the oil pump
Does not move forward
If the vehicle does not move forward when
the selector lever is shifted from N to D, 3, 2
or L range while the engine is idling, the
cause is probably abnormal line pressure or a
malfunction of the underdrive clutch or valve
body. a.
Abnormal line pressure
b. Malfunction of the underdrive solenoid
valve
c. Malfunction of the underdrive clutch
d. Malfunction of the valve body
Does not reverse
If the vehicle does not reverse when the
selector lever is shifted from N to R range
while the engine is idling, the cause is
probably abnormal pressure in the reverse
clutch or low and reverse brake or a
malfunction of the reverse clutch, low and
reverse brake or valve body. a.
Abnormal reverse clutch pressure
b. Abnormal low and reverse brake pressure
c. Malfunction of the low and reverse brake
solenoid valve
d. Malfunction of the reverse clutch
e. Malfunction of the low and reverse brake
f. Malfunction of the valve body
Does not move (forward or reverse)
If the vehicle does not move forward or
reverse when the selector lever is shifted to
any position while the engine is idling, the
cause is probably abnormal line pressure or a
malfunction of the power train, oil pump or
valve body. a.
Abnormal line pressure
b. Malfunction of power train
c. Malfunction of the oil pump
d. Malfunction of the valve body
Malfunction when
starting Engine stalling when shifting
If the engine stalls when the selector lever is
shifted from N to D or R range while the
engine is idling, the cause is probably a
malfunction of the engine system, damper
clutch solenoid valve, valve body or torque
converter (damper clutch malfunction). a.
Malfunction of the engine system
b. Malfunction of the damper clutch control
solenoid valve
c. Malfunction of the valve body
d. Malfunction of the torque converter
(Malfunction of the damper clutch)
Shocks when changing from N to D and large
time lag
If abnormal shocks or a time lag of 2 seconds
or more occur when the selector lever is
shifted from N to D range while the engine is
idling, the cause is probably abnormal
underdrive clutch pressure or a malfunction of
the underdrive clutch, valve body or idle
position switch. a.
Abnormal underdrive clutch pressure
b. Abnormal low and reverse brake pressure
c. Malfunction of the underdrive solenoid
valve
d. Malfunction of the valve body
e. Malfunction of the idle position switch
Malfunction when
starting Shocks when changing from N to R and large
time lag
If abnormal shocks or a time lag of 2 seconds
or more occur when the selector lever is
shifted from N to R range while the engine is
idling, the cause is probably abnormal reverse
clutch pressure or low and reverse brake
pressure, or a malfunction of the reverse
clutch, low and reverse brake, valve body or
idle position switch. a.
Abnormal reverse clutch pressure
b. Abnormal low and reverse brake pressure
c. Malfunction of the low and reverse
solenoid valve
d. Malfunction of the reverse clutch
e. Malfunction of the low and reverse brake
f. Malfunction of the valve body
g. Malfunction of the idle position switch
Shocks when changing from N to D, N to R
and large time lag
If abnormal shocks or a time lag of 2 seconds
or more occur when the selector lever is
shifted from N to D range and from N to R
range while the engine is idling, the cause is
probably abnormal line pressure or a
malfunction of the oil pump or valve body.a.
Abnormal line pressure
b. Malfunction of the oil pump
c. Malfunction of the valve body
Malfunction when
shifting Shocks and running up
If shocks occur when driving due to up
shifting or down shifting and the transmission
speed becomes higher than the engine
speed, the cause is probably abnormal line
pressure or a malfunction of a solenoid valve,
oil pump, valve body or of a brake or clutch. a.
Abnormal line pressure
b. Malfunction of each solenoid valve
c. Malfunction of the oil pump
d. Malfunction of the valve body
e. Malfunction of each brake or each clutch
Displaced shifting
points All points
If all shift points are displaced while driving,
the cause is probably a malfunction of the
output shaft speed sensor, TPS or of a
solenoid valve. a.
Malfunction of the output shaft speed
sensor
b. Malfunction of the throttle position sensor
c. Malfunction of each solenoid valve
d. Abnormal line pressure
e. Malfunction of the valve body
f. Malfunction of the TCM(PCM)
Some points
If some of the shift points are displaced while
driving, the cause is probably a malfunction of
the valve body, or it is related to control and
is not an abnormality. a.
Malfunction of the valve body
Does not shift No diagnosis codes
If shifting does not occur while driving and no
diagnosis codes are output, the cause is
probably a malfunction of the transaxle range
switch, or TCM(PCM) a.
Malfunction of the transaxle range
b. Malfunction of the TCM(PCM)
Malfunction while
driving Poor acceleration
If acceleration is poor even if down shifting
occurs while driving, the cause is probably a
malfunction of the engine system or of a
brake or clutch. a.
Malfunction of the engine system
b. Malfunction of the brake or clutch
Malfunction while
driving Vibration
If vibration occurs when driving at constant
speed or when accelerating and deceleration
in top range, the cause is probably abnormal
damper clutch pressure or a malfunction of
the engine system, damper clutch control
solenoid valve, torque converter or valve
body. a.
Abnormal damper clutch pressure
b. Malfunction of the engine system
c. Malfunction of the damper clutch control
solenoid valve
d. Malfunction of the torque converter
e. Malfunction of the valve body
Transaxle range switch system
The cause is probably a malfunction of the inhibitor switch circuit,
ignition switch circuit or a defective TCM(PCM). a.
Malfunction of the transaxle range switch
b. Malfunction of the ignition switch
c. Malfunction of connector
d. Malfunction of the TCM(PCM)
Idle position switch system
The cause is probably a defective idle position switch circuit, or a
defective TCM(PCM). a.
Malfunction of the triple pressure switch
b. Malfunction of connector
c. Malfunction of the TCM(PCM)